Stent with enhanced friction

Abstract

A stent for placement in a body lumen is fabricated by forming a tube having an undeployed diameter sized for the tube to be placed on a deployment balloon and advanced through a body lumen to a deployment site. The tube is expandable upon inflation of the balloon to an enlarged diameter sized for the tube to be retained within the lumen at the site upon deflation and withdrawal of the balloon. The tube has a stent axis extending between first and second axial ends of the tube. The tube has an exterior surface and an interior surface. The tube is polished to polish the exterior surface to a smooth surface finish and with at least a portion of the interior surface having a rough surface finish rougher than the surface finish of the exterior surface.

What is claimed is: 
     
       1. An intravascular device comprising:
 a tubular stent body expandable from an undeployed configuration to a deployed configuration, the stent body defining an exterior surface and an interior surface arranged about a stent axis, wherein some areas of the interior surface have a roughened surface finish and other areas of the interior surface are devoid of the roughened surface finish, the some areas having the roughened surface finish being on opposite sides of a center line of the stent body, the center line being orthogonal to the stent axis, 
 wherein substantially all of the exterior surface of the stent body has a generally smooth finish relative to the roughened surface finish of the interior surface, 
 wherein the stent body includes a plurality of ribs defining openings extending through the stent body from the interior surface to the exterior surface, and 
 wherein the roughened surface finish of the interior surface defines pits having a maximum dimension of approximately 3 microns to approximately 20 microns in size. 
 
     
     
       2. The intravascular device of  claim 1 , the ribs having radial surfaces extending from the interior surface to the exterior surface, wherein the radial surfaces have the roughened surface finish. 
     
     
       3. The intravascular device of  claim 1 , wherein the roughened surface finish extends along the stent axis and is spaced from axial ends of the stent body such that axial end segments of the interior surface are devoid of the roughened surface finish and a central segment between the axial end segments has the roughened surface finish. 
     
     
       4. The intravascular device of  claim 1 , wherein the some areas having the roughened surface finish surround the stent axis. 
     
     
       5. The intravascular device of  claim 1 , wherein the stent body is formed from metal. 
     
     
       6. The intravascular device of  claim 1 , wherein the exterior surface is polished to a smooth surface finish. 
     
     
       7. The intravascular device of  claim 1 , wherein the stent body is formed from titanium, Nitinol, or stainless steel. 
     
     
       8. A system comprising:
 a catheter comprising a balloon; 
 a stent placed on the catheter surrounding the balloon, the stent comprising:
 a stent body expandable from an undeployed configuration to a deployed configuration, the stent body defining an exterior surface and an interior surface arranged about a stent axis, wherein some areas of the interior surface have a roughened surface finish and other areas of the interior surface are devoid of the roughened surface finish, the some areas having the roughened surface finish being on opposite sides of a center line of the stent body, the center line being orthogonal to the stent axis, 
 wherein substantially all of the exterior surface of the stent body has a generally smooth finish relative to the roughened surface finish of the interior surface, 
 wherein the stent body includes a plurality of ribs defining openings extending through the stent body from the interior surface to the exterior surface, wherein 
 the roughened surface finish of the interior surface defines pits having a maximum dimension of approximately 3 microns to approximately 20 microns in size, and wherein 
 
 wherein the balloon is configured to be inflated to expand the stent to the deployed configuration. 
 
     
     
       9. The system of  claim 8 , wherein the roughened surface finish extends along the stent axis and is spaced from axial ends of the stent body such that axial end segments of the interior surface are devoid of the roughened surface finish and a central segment between the axial end segments has the roughened surface finish. 
     
     
       10. A method comprising:
 creating a roughened surface finish for some areas of an interior surface of a tubular stent body, the stent body being expandable from an undeployed configuration to a deployed configuration, and defining an exterior surface and the interior surface arranged about a stent axis, 
 wherein some areas of the interior surface have the roughened surface finish and other areas of the interior surface are devoid of the roughened surface finish, the some areas having the roughened surface finish being on opposite sides of a center line of the stent body, the center line being orthogonal to the stent axis, wherein substantially all of the exterior surface of the stent body has a generally smooth finish relative to the roughened surface finish, 
 wherein the stent body includes a plurality of ribs defining openings extending through the stent body from the interior surface to the exterior surface, and 
 wherein creating the roughened surface finish comprises defining pits having a maximum dimension of approximately 3 microns to approximately 20 microns in size in the interior surface. 
 
     
     
       11. The method of  claim 10 , wherein creating the roughened surface finish comprises directing a particulate stream at the interior surface of the stent body at an angle relative to the stent axis. 
     
     
       12. The method of  claim 11 , wherein directing the particulate stream at the interior surface of the stent body comprises positioning a nozzle adjacent an end of the stent body, wherein the particulate stream exits the nozzle. 
     
     
       13. The method of  claim 12 , wherein the end is a first end, the method further comprising inserting a rod through a second end of the stent body to expose only the some areas. 
     
     
       14. The method of  claim 11 , further comprising rotating the stent body about the stent axis while directing the particulate stream at the interior surface of the stent body. 
     
     
       15. The method of  claim 11 , wherein the particulate stream comprises powder silicon carbide. 
     
     
       16. The method of  claim 11 , further comprising polishing the exterior surface of the stent body.